goTenna | Text & GPS on your phone, even without service.
goTenna turns your iPhone or Android into an off-grid communications tool, enabling you to text & share GPS locations on detailed offline maps. goTenna is lightweight, weather-proof, and easy to use. goTenna is sold in pairs — 2, 4, 6 or more! — so you can stay connected to at least one friend (and anyone else using goTenna).
Each pair comes with 2 micro-USB charging cables. goTenna apps and offline maps are free to download. goTenna comes with a 1-year limited warranty.